The accurate location of user equipment, such as a GSM (Global System for Mobile Communications) mobile device, cannot be determined using the information from a cellular network. The information enables the location only of an accuracy of about 100-300 meters in rural areas and 50-100 meters in city areas. For example, in a case of an emergency call, it is vital to find out the exact location from which the call was made to be able to get help to the site as fast as possible.
For better accuracy, one possibility is the use of GPS (Global Positioning System) receivers, which offer better accuracy. However, they are expensive and not widely carried and used by public. In addition, GPS receivers do not work reliably or at all indoors and in canyons, like in between high buildings.
Another possibility is to add high accuracy satellite positioning system functionality to the existing non-satellite positioning system user equipment without any modifications to the equipment itself but only by inserting a subscriber identity module, a SIM card comprising a satellite positioning system receiver and an antenna.
However, the problem with the SIM card with such a receiver and especially an antenna is the radio signal reception. One of the disadvantages associated with the above arrangement is that the receiver and antenna are inside the mobile device in proximity of a ground plane and other metallic parts and often covered with a battery. In this kind of circumstances traditional antennas are too big and do not work.
US 2002/0082992 A1 discloses a chip card with an integrated time-determining system and a billing method for billing a call to a user identified with an identification card in a telecommunications network. In it a GPS receiver determines the duration of the calls. An advantage of the invention is that the user cannot falsify the determined time.
U.S. 2004/0246180 A1 discloses a dielectric antenna, an antenna mounted substrate and a mobile communication machine. The dielectric antenna has a dielectric base, a linear element, at least one bending portion, a power supply terminal, a linear conductor and a ground terminal.
WO 98/58509 A discloses a chip card method for communication between an external device and a chip card. The chip card contains at least one coil for establishing communication via radio waves between said processing system and external device outside the mobile communication station.
U.S. Pat. No. 6,580,397 B2 discloses an arrangement for a mobile terminal. An antenna system comprises a casing, a screening device, an end-fed antenna and a counterpoise element. The end-fed antenna is adapted to be fed, during transmission, against the counterpoise element by the radio electronic circuits.